IPv4 Header Fields Explained

Background + 1:29 Header fields discussion IPv4 header fields makes the header part of IP packet. Different fields and their jobs are: Source IP Address: contains a 32-bit binary representing IP address of sending node Destination IP Address: contains a 32-bit binary representing IP address of destination node Version: indicates the version of IP (IPv4 or IPv6) Length (4-bits): represents the maximum length of header Packet Length (16-bits): represent the maximum length of packet. Max. packet length = 2^16= 65535 DS (Differentiated Services) Field: this is replacement of Type of Service (TOS) field It defines different level of service a packet receives in the network Identification: Sent by the source to help reassemble any fragments Flags: indicates for instance if a packet is allowed to be fragmented or not and related matters Fragment Offset: The Fragment Offset, along with the Identification field, is used to identify packets that have been fragmented and reassemble them in the correct order. DS (Differentiated Services) Field: this is replacement of Type of Service (TOS) field It defines different level of services a packet receives in the network. Services include, delay throughput, reliability etc. Identification: Sent by the source to help reassemble any fragments Time to Live: describes the maximum hops the packet can take before it is considered lost Protocol: field used to identify the upper-layer protocol—for example, TCP, UDP or ICMP Header Checksum : Algorithm used by the routers to check the validity of the packet being processed Options: Used to provide special routing services Padding: extra bits added to make header multiple of 32 bits #IPv4HeaderFields